TFT-LCD of ADSDS (ADvanced Super Dimension Switch, abbreviated as ADS) mode is widely used in the liquid crystal display field due to its advantages of high resolution, high transmittance, low power consumption, wide viewing angle, high aperture ratio, low chromatic aberration, free of push Mura, etc. In the TFT-LCD of ADS mode, a multi-dimensional electric field is formed with both an electric field generated at edges of slit electrodes in a same plane and an electric field generated between a slit electrode layer and a plate-like electrode layer, so that liquid crystal molecules at all orientations, which are located directly above the electrodes or between the slit electrodes in a liquid crystal cell, can be rotated. In this way, the work efficiency of liquid crystal can be enhanced, the light transmittance can be increased, and thus the image quality of the TFT-LCD can be improved.
At present, an array substrate of the ADS mode TFT-LCD may be formed by a plurality of patterning processes, and each of the patterning processes may further comprises a film forming process, an exposing process, a developing process, an etching process, a stripping process and so on. The etching process may be a dry etching process or a wet etching process.
FIG. 1 is a schematic structural view of an array substrate of a conventional ADS mode TFT-LCD. As shown in FIG. 1, a common electrode 2 and a gate electrode 4 are provided in a same layer, and a patterning process for forming the common electrode 2 and a patterning process for forming the gate electrode 4 are performed sequentially. The common electrode 2 and the gate electrode 4 may be electrically connected to each other if residuals of the common electrode 2 or the gate electrode 4 are generated in the corresponding patterning process, in this case, a short circuit (Gate-Common Short) occurs between the common electrode 2 and the gate electrode 4 and the properties of the thin film transistor will be severely deteriorated. In order to prevent such short circuit phenomenon, the distance between the common electrode 2 and the gate electrode 4 is generally increased. However, when the distance between the common electrode 2 and the gate electrode 4 is increased, the width of a black matrix (BM) used to prevent light leakage has to be increased, the light transmitting region of each pixel unit has to be decreased, and thus the aperture ratio of each pixel unit will be reduced.